Active and passive monitoring of fault reactivation under stress cycling

Abstract

Increased seismicity due to subsurface activities has led to increased interest in monitoring and seismic risk mitigation. In this study we combined passive and active acoustic monitoring methods to monitor fault sliding and reactivation in the laboratory. Acoustic emission (AE) and ultrasonic transmission measurements were performed during stress-cycling to monitor stress-driven fault reactivation. We show the use of the transmissivity and coda wave interferometry of the active acoustic measurements and the number of generated AE events for fault reactivation monitoring. Combining these two methods, we are able to detect the different phases of fault reactivation process under stress cycling including, early aseismic creep (pre-slip), fault slip, and continuous sliding. Combining both active and passive monitoring increases accuracy of monitoring and can lead to better seismic risk mitigation